My chicks are 6 weeks old now, and their coop is almost done, but due to ongoing family emergencies it's not done enough that they can use it. It will be done by the weekend. They have been going out daily in their run, which is half covered with a tarp, but it has been in the 70's with sun. Today is off and on rain and much colder- like 50*. They are crowded and unhappy right now in their brooder box- which is a big hot water heater box. Is it too cold to let them go outside today if I provide them a box to get in with some pine shavings in case they want to warm up?